White House: Obama-Castro handshake not 'pre-planned'

12/10/13 6:54 AM EST

As President Obama made his way through a crowd of 90 other world leaders in Johannesburg on Tuesday, he shook a surprising hand: that of Cuban President Raul Castro.

Video cameras caught the handshake, which came as Obama reached out to dozens of other leaders during the song that preceded his eulogy of Mandela

The moment was not "a pre-planned encounter," a White House official said. "Above all else, today is about honoring Nelson Mandela, and that was the president's singular focus at the memorial service. We appreciate that people from all over the world are participating in this ceremony."

Though undoubtedly a polite gesture meant to honor Mandela's legacy, the handshake also comes not long after Obama indicated a desire to update U.S. policies toward Cuba.

"We have to be creative and we have to be thoughtful and we have to continue to update our policies," he said at a fundraiser in Florida last month, noting that Fidel Castro came to power more than half a century ago.

"I think we all understand that ultimately, freedom in Cuba will come because extraordinary activists and the incredible courage of folks like we see here today," he said. "But the United States can help."

The White House official reiterated that, as Obama said in his speech Tuesday, the United States urges "leaders to honor Mandela's struggle for freedom by upholding the basic human rights of their people."

A Cuban government website posted a photo of the handshake within hours and suggested it might be more than just a cordial gesture.

“Obama greets Raul: may this image be the beginning of the end of the US aggressions against Cuba," the photo's caption reads.